Previously, Lyft accused Uber of calling and then canceling more than 5,000 rides on its service, costing its drivers time and money.

"Would it be controversial if we got in taxis and recruited taxi drivers and paid for the ride?" Kalanick tweeted, adding, "to be clear, we are paying for the rides, these are independent contractors working for multiple co's."

Both services are popular in San Francisco. News of the tactics, reported by the Verge, spread quickly on Twitter where all sorts of Valley bigwigs jumped in with opinions on it.

Jason Fried, founder & CEO at Basecamp (formerly known as 37signals) started the debate by taking Uber to task. In a series of tweets we've condensed that begin here, Fried tweeted:

I *understand* the @uber recruiting angle. A $10 ride is the cheapest way to get in front of a strong lead/candidate…

…it's just more about how it all /feels/. Like someone walking into your physical office, pulling up a chair, and recruiting your people…

…you'd surely kick them out of your office. You might even call the cops if they didn't leave…

…It doesn't matter if they left a $10 bill in the tip jar on their way out.

Regardless, I still have deep respect for @uber and @travisk. I love the product. I'm a regular customer. What they've built is amazing…

…and we're all entitled to a handful of bumps in the road when building our businesses… Just hope they do more of the great stuff.

That caused Kalanick to reply and also caused Fried's cofounder and CTO of Basecamp, David Heinemeierhansson (@dhh), to jump in. (Heinemeierhansson is famous in the tech world for inventing a super popular Web programing language called Ruby on Rails.)